 Very early in Brechen's history, there was a Roman military camp in what is now the municipal area, at a site now known as Alteburg (“High Castle”), lying on the Emsbach.The camp's south frontage has a length of 140 m joining two sidewalls with respective lengths of 90 and 135 m.

The camp came to light after finds made with metal detectors led the regional archaeologist Dr. Schade-Lindig from the Hesse state office for memorial maintenance to carry out the first investigations in the "Großer Wald" (“Great Forest”) east of Oberbrechen between 1999 and 2001.Lying near a group of Hallstatt-era barrows, the site had long been known to contain something historical, but since it had never been properly investigated, it had always been taken to be a sconce from the Thirty Years' War (1618–1648).